Instrumentation Package in a Downhole Tool String Component

ABSTRACT

A downhole tool string component has a through-bore intermediate first and second tool joints adapted for connection to adjacent tool string components. An instrumentation package is disposed within an outer diameter of the component. The instrumentation package comprises a circuit board assembly. The circuit board assembly comprises alternating rigid and elastomeric layers. The rigid layers are in electrical communication with each other.

BACKGROUND OF THE INVENTION

The present invention is related to gaining access to data from a drillstring especially for oil, gas, and geothermal well exploration andproduction particularly to an electrical assembly for use in downholedrilling string components. Information such as temperature, pressure,inclination, salinity, etc. is of great valve while drilling which cansave time and money.

U.S. patent application Ser. No. 11/590,229 to Hanley, which is hereinincorporated by reference for all that it contains discloses anelectronic assembly for use in a downhole tool includes a damming bootdeployed about at least one integrated circuit component on a circuitboard. The boot is disposed to house the integrated circuit leads andsolder joints in a substantially sealed cavity between the circuitboard, the integrated circuit body, and an inner surface of the dammingboot. The boot is also disposed to support the integrated circuit bodyand thereby improve the shock and vibration resistance of variouselectronic assemblies used in downhole tools. The invention also tendsto improve the reworkability of downhole electronic assemblies.

U.S. Pat. No. 6,225,688 to Kim et al., which is herein incorporated byreference for all that it contains, discloses a stacked microelectronicassembly and its resulting structure includes a flexible substratehaving a plurality of attachment sites, test contacts and conductiveterminals, and including a wiring layer with leads extending to theattachment sites. The assembly includes a plurality of microelectronicelements assembled to the attachment sites and electricallyinterconnecting the microelectronic elements and the leads. The flexiblesubstrate is folded so as to stack at least some of the microelectronicelements in substantially vertical alignment with one another to providea stacked assembly with the conductive terminals exposed at the bottomend of the stack and the test contacts exposed at the top end of thestack. The assembly may be made using a dam and or a spacer tofacilitate the folding process. Two stacked microelectronic assembliesmay be stacked together by providing a first stacked assembly with aplurality of connection pads exposed at the top end and providing asecond stacked assembly with a plurality of solder balls connected tothe terminals at the bottom end. The first and second assemblies may bestacked by connecting the solder balls to the connection pads.

U.S. Pat. No. 7,167,373 to Hoang, which is herein incorporated byreference for all it contains, discloses one embodiment of the inventionwhich includes a flexible circuit and a stiffener. The flexible circuithas first, second, and third portions. The first portion is folded on anupper surface of the third portion and has first contact elementsattached to a first device. The second portion is folded on the firstdevice and has second contact elements attached to a second device. Thestiffener is attached to the upper surface of the third portion andlocated between the upper surface of the third portion and the firstportion.

U.S. Pat. No. 7,158,384 to Huang, which is herein incorporated byreference for all that it contains, discloses a vibration reducingstructure of an electronic device includes first and second housings, aprinted circuit board, a first post and a second post. The first andsecond housings define a closed space there between. The printed circuitboard is disposed within the space and having a heavy component mountedon a first surface thereof. The first post is arranged on the firsthousing and under the heavy component. The second post is arranged onthe second housing and above the heavy component.

BRIEF SUMMARY OF THE INVENTION

A downhole tool string component has a through-bore intermediate firstand second tool joints adapted for connection to adjacent tool stringcomponents. An instrumentation package is disposed within an outerdiameter of the component. The instrumentation package comprises acircuit board assembly. The circuit board assembly comprises alternatingrigid and elastomeric layers. The rigid layers are in electricalcommunication with each other.

The instrumentation package may be disposed within the through-bore. Thecircuit board assembly, disposed within the instrumentation package, maybe aligned with a longitudinal central axis of the through-bore. Theinstrumentation package may be laterally centered within thethrough-bore, such that drilling mud is adapted to flow between theouter surface of the instrumentation package and the through-bore wall.

At least two rigid layers of the circuit board assembly may be inelectrical communication with each through a flexible connector. Theflexible connector may comprise a single or multi layer flexible printedcircuit board. The flexible connector may comprise a polyimide material.The rigid layers and flexible connectors may comprise a rigid-flexiblecircuit board that has been folded and stacked up onto itself. The rigidlayers may comprise stiffeners.

The circuit board assembly may be disposed within a removable housing. Afirst end of the circuit board assembly may comprise an electricalconnector adapted to communicate with a first electrical device and asecond end of the circuit board assembly may comprise another electricalconnector adapted to communicate with a second electrical device. Theelastomeric material may be injected into the circuit board assembly.The circuit board assembly may comprise at least one anti-settlingelement adapted to prevent at least two boards from contacting eachother.

The circuit board assembly may control a steerable downhole assembly.The circuit board assembly may be a processing unit for downholeelectrical devices. The circuit board assembly may be in communicationwith a drill string telemetry system. The circuit board assembly mayreceive power from a downhole power generation system. The circuit boardassembly may be disposed within a through-bore wall. The circuit boardassembly may be disposed within a pocket formed by a sleeve surroundingthe through-bore. The circuit board assembly may comprise a tube runningthe entire length of the package such that drilling mud is adapted toflow within the package through the tube.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional diagram of an embodiment of a drill stringsuspended in a wellbore.

FIG. 2 is a cross sectional diagram of an embodiment of a downholecomponent.

FIG. 3 is a cross sectional diagram of an embodiment of a circuit boardassembly.

FIG. 4 a is a cross sectional diagram of another embodiment of a circuitboard assembly.

FIG. 4 b is a extended diagram of another embodiment of a circuit boardassembly.

FIG. 5 is a cross sectional diagram of another embodiment of a circuitboard assembly.

FIG. 6 a is a cross sectional diagram of another embodiment of a circuitboard assembly.

FIG. 6 b is a cross sectional diagram of another embodiment of a circuitboard assembly.

FIG. 7 is a cross sectional diagram of another embodiment of a circuitboard assembly.

DETAILED DESCRIPTION OF THE INVENTION AND THE PREFERRED EMBODIMENT

FIG. 1 is a perspective diagram of an embodiment of a drill string 100suspended by a derrick 101. A bottom-hole assembly 102 is located at thebottom of a wellbore 103 and comprises a drill bit 104. As the drill bit104 rotates downhole the drill string 100 advances farther into theearth. The drill string 100 may penetrate soft or hard subterraneanformations 105. The drill bit 104 may be adapted to steer the drillstring 100 in a desired trajectory. Steering may be controlled byrotating a jack element (see FIG. 2) that is disposed at least partiallywithin the drill bit 104 around a central axis of the jack element. Thebottom-hole assembly 102 and/or downhole components may comprise dataacquisition devices which may gather data. The data may be sent to thesurface via a transmission system to a data swivel 106. The data swivel106 may send the data to the surface equipment. Further, the surfaceequipment may send data and/or power to downhole tools and/or thebottom-hole assembly 102. U.S. Pat. No. 6,670,880 which is hereinincorporated by reference for all that it contains, discloses atelemetry system that may be compatible with the present invention;however, other forms of telemetry may also be compatible such as systemsthat include mud pulse systems, electromagnetic waves, radio waves,and/or short hop. In some embodiments, no telemetry system isincorporated into the drill string.

Referring now to FIG. 2, a cross-sectional diagram of drill string 100discloses a bottom hole assembly (BHA) 102. The drill bit 104 may bepart of the BHA 102 and comprises a jack element 201. The jack element201 may oscillate towards and away from the formation 105 and/or thejack element 201 may rotate around an axis. The drill string maycomprise an instrumentation package. The instrumentation package 213 maycomprise sensors, generators, circuit boards, processing units, or anyother electronic device adapted for downhole operation. The drill stringmay comprise at least one position feedback sensor 202 that is adaptedto detect a position and/or orientation of the jack element 201.Monitoring the position and/or orientation of the jack element 201 mayaid in steering the drill string 100. Rotation of the jack element 201may be powered by a driving mechanism, such as a downhole motor 203. Thedownhole motor 203 may be an electric motor, a mud motor, orcombinations thereof. In the present embodiment, drill string 100comprises an upper generator 204 and a lower generator 205. Bothgenerators 204, 205 are powered by the flow of drilling mud (not shown)past one or more turbines 206 disposed intermediate the two generators204, 205. Ports 211, 212 within the drill string component may beadapted to divert drilling mud from the interior of the through bore toa channel within the inner wall of the through bore such that thedrilling mud flows around components that are disposed within theinterior of the through bore. In some embodiments only one generator maybe used, or another method of powering the motor 203 may be employed.

The upper generator 204 may provide electricity to a direction andinclination (D&I) package 207. D&I package 207 may monitor theorientation of the BHA 102 with respect to some relatively constantobject, such as the center of the planet, the moon, the surface of theplanet, a satellite, or combinations thereof. The lower generator 205may provide electrical power to a circuit board assembly 208 and to themotor 203. The circuit board assembly 208 may control steering and/ormotor functions. The circuit board assembly 208 may receive drill stringorientation information from the D&I package 207 and may alter the speedor direction of the motor 203.

In the present embodiment a jack assembly 301 is disposed in a terminalregion 210 of the drill string 100 and may be adapted to rotate withrespect to the drill string 100 while the motor 203 may be rotationallyfixed to the drill string 100. In some embodiments one or more motor203, generator 204, 205, circuit board assembly 208, D&I package 207, orsome other electrical component, may be rotationally isolated from thedrill string 100. In the present embodiment the motor 203 connects tothe jack element 201 via a gear train 209. The gear train 209 may couplerotation of the motor 203 to rotation of the jack element 201 at a ratioof 25 rotations to 1 rotation and may itself be rotationally fixed tothe drill string 100. In some embodiments a different ratio may be used.The gear train 209 and the jack element 201 may be part of the jackassembly 301.

FIG. 3 is a cross sectional view of a diagram of an embodiment of acircuit board assembly 208 that may be aligned with a longitudinalcentral axis 309 of the through bore and may be laterally centeredwithin the through bore. The circuit board assembly may be disposedwithin a removable housing 306. The removable housing containing thecircuit board assembly may be disposed within the instrumentationpackage. The circuit board assembly may be positioned such that drillingmud is adapted to flow in a channel 307 between a through bore wall 310and an outer surface 308 of the housing. It is believed that thedrilling mud may act as a cooling agent as it flows around the circuitboard assembly.

The circuit board assembly may comprise alternating rigid 302 andelastomeric layers 301. The elastomeric layers 301 may be injected intothe housing such it is dispersed between the rigid layers 302. In someembodiments, the elastomeric layers are connected together. The rigidlayers 302 may comprise printed circuit boards. The printed circuitboards may be in communication with each other through a flexibleconnector 303. The flexible connector 303 may comprise a single ormulti-layer flexible printed circuit board. The rigid layers 302 inconjunction with the flexible connectors 303 may comprise arigid-flexible circuit board that was been stacked up on itself. Eitherthe rigid layers or the flexible connector may be comprised of apolyimide material. It is believed that due to higher temperaturetolerances the polyimide material may provide better performance in adownhole environment. The elastomeric layers may accommodate fordownhole vibrations and shocks while the flexible connectors maintainelectrical communication. Vibrations may be induced from the rotarycutting action of the drill bit, firing of tool string jars and otherdownhole tools or combinations thereof.

A first end of the circuit board assembly 208 may comprises anelectrical connector 304 adapted to communicate with a first electricaldevice and a second end of the circuit board assembly may compriseanother electrical connector 305 adapted to communicate with a secondelectrical device. The first and second electrical devices may comprisea drill string telemetry system 308. The circuit board assembly 208 maycontrol a steerable downhole assembly 102. An example of a steerabledownhole assembly that may be compatible with the present invention isdisclosed in U.S. patent application Ser. No. 11/851,094 to Hall, whichis herein incorporated by reference for all that it discloses. Thecircuit board assembly 208 may be a processing unit for downholeelectrical devices. The circuit board assembly 213 may receive powerfrom a downhole power generation system 204, 205. An example of adownhole power generation system that may be compatible with the presentinvention is disclosed in U.S. patent application Ser. No. 11/940,091 toHall, which is herein incorporated by reference for all that itdiscloses.

In some embodiment, the elastomeric layers are also thermally conductiveallowing immense heat from hot spots formed on the circuit boards to bespread quickly throughout the layers. In embodiments, where the circuitboard assembly is located within the through bore of the downhole toolstring component, the drilling mud may further absorb the heat as itpasses by. In some embodiments the circuit board assemblies mayincorporate thermally conductive spurs which contact both theelastomeric layers and the drilling mud directly.

FIG. 4 a is a cross sectional diagram of an embodiment of a circuitboard assembly 208. The elastomeric material has been removed forillustration purposes. In FIG. 4 a the rigid layers may comprise aflexible printed circuit board 403 with stiffeners 404. The flexiblecircuit board may also function as a connector 402. The embodimentdepicted in FIG. 4 a also discloses anti-settling devices 401 which mayprevent the rigid layers 404, 403 from contacting each other.

FIG. 4 b is an extended diagram of an embodiment of a circuit boardassembly board. The circuit board assembly may comprise stiffeners 302.The connectors 303 may comprise flexible printed circuit boards. Theprinted circuit board may have a first connector 304 at one end of thecircuit and a second connector 305 at the other end of the circuit.

FIG. 5 is a diagram of another embodiment of a circuit board assembly208. In the embodiment depicted in FIG. 5 the elastomeric layers 301 maybe in the shape of rings such that they contact the rigid layer on theouter edges. This may create a cavity 504 between each rigid layer. Theconnectors 303 may connect the rigid layers through this cavity.

FIGS. 6 a and 6 b both are diagrams of different embodiments of circuitboard assemblies. In FIG. 6 a the circuit board assembly 208 may bedisposed within a pocket 602 formed between a sleeve 601 and an outersurface of a through-bore wall 310. An example of a pocket formed in asleeve that may be compatible with the present invention is disclosed inU.S. patent application Ser. No. 11/688,952 by Hall et al which isherein incorporated by reference for all that it discloses. FIG. 6 bdepicts a circuit board assembly 208 disposed with the through-bore wall310. The vertical axis of the circuit board assembly may beperpendicularly aligned with the longitudinal axis of the through bore.

FIG. 7 is a diagram of an embodiment of a circuit board assembly 208.The circuit board assembly may comprise a tube 401 running the entirelength of the assembly such that drilling mud is adapted to flow throughthe assembly within the tube. The rigid 302 and elastomeric 301 layersmay be formed such that they have a circle cut out of their approximatecenters thereby providing a path for the tube to travel through theassembly. The drilling mud accommodated by the tube may cool the circuitas it passes through. The tube may also provide additional lateralstability to the circuit board assembly.

Whereas the present invention has been described in particular relationto the drawings attached hereto, it should be understood that other andfurther modifications apart from those shown or suggested herein, may bemade within the scope and spirit of the present invention.

1. A downhole tool string component, comprising: a through-boreintermediate first and second tool joints adapted for connection toadjacent tool string components; an instrumentation package beingdisposed within an outer diameter of the component and comprising acircuit board assembly; the circuit board assembly comprising aplurality of stacked alternating rigid and elastomeric layers; and therigid layers being in electrical communication with each other.
 2. Thecomponent of claim 1, wherein the circuit board assembly is disposedwithin the through-bore and the circuit board assembly is aligned with alongitudinal central axis of the through-bore.
 3. The component of claim1, wherein circuit board assembly is laterally centered within thethrough-bore such that drilling mud is adapted to flow between athrough-bore wall and an outer surface of the package.
 4. The componentof claim 1, wherein a first rigid layer is in electrical communicationwith a second rigid layer through a flexible connector.
 5. The componentof claim 4, wherein the flexible connector comprises a single ormultilayer flexible printed circuit board.
 6. The component of claim 4,wherein the flexible connector comprises a polyimide material.
 7. Thecomponent of claim 1, wherein the circuit board assembly is comprised ofa rigid-flexible circuit board that has been folded so as to stack up onitself.
 8. The component of claim 1, wherein the elastomeric layers areinjected into the circuit board assembly.
 9. The component of claim 1,wherein the circuit board assembly is disposed within a removablehousing.
 10. The component of claim 1, wherein a first end of thecircuit board assembly comprises an electrical connector adapted tocommunicate with a first electrical device and a second end of thecircuit board assembly comprises another electrical connector adapted tocommunicate with a second electrical device.
 11. The component of claim1, wherein the circuit board assembly electrically controls a steerabledownhole assembly.
 12. The component of claim 1, wherein the circuitboard assembly is a processing unit for downhole electrical devices. 13.The component of claim 1, wherein the circuit board assembly is incommunication with a drill string telemetry system.
 14. The component ofclaim 1, wherein the circuit board assembly receives power from adownhole power generation system.
 15. The component of claim 1, whereinat least one of the rigid layers is a printed circuit board comprisingstiffeners.
 16. The component of claim 1, wherein the circuit boardassembly comprises at least one anti-settling element adapted to preventat least two of the rigid layers from contacting each other.
 17. Thecomponent of claim 1, wherein the circuit board assembly is disposedwithin a through-bore wall.
 18. The component of claim 1, wherein thecircuit board assembly is disposed within a sleeve surrounding thethrough-bore.
 19. The component of claim 1, wherein the circuit boardassembly comprises a tube running the entire length of the package suchthat drilling mud is adapted to flow within the package through thetube.